Research on Calculation Method of Shielding Effectiveness of Irregular Cavity

Based on the Transmission Line Method and Electromagnetic Topology theory, this paper proposes an analytical calculation method for solving the shielding effectiveness of irregular cavities. This method equates the apertures and the special-shaped structures into two-port networks, constructs the signal flow diagram based on the equivalent transmission line model, derives the scattering matrices, and solves the shielding effectiveness of the irregular cavity through the generalized BLT equation. Several typical structures are analyzed and the results are in good agreement with CST simulation when frequency exceeds the first resonant frequency of the cavity. The method can quickly obtain the shielding effectiveness and resonance characteristics of the irregular cavity with different structures, and the special-shaped structures are classified according to their features, which has guiding significance for the shielding effectiveness test of the irregular cavity.